We seek to identify one or more genes important in the genesis of some forms of hereditary retinal degeneration in humans. For this project, we have obtained blood samples from over 1300 patients with some form of inherited retinal disease, with particular emphasis on patients with autosomal dominant, autosomal recessive, or the "isolate" form of retinitis pigmentosa. Included in this collection are affected and unaffected relatives from a number of pedigrees with two or more affected individuals. This collection is, to the best of our knowledge, an unrivaled genetic material (DNA) derived from this set of blood sample will allow studies aimed at identifying the genes involved in these diseases and subsequently characterizing the mechanism of action, ancestral origin, and DNA sequence of the responsible mutations. The experiments that we wish to perform are based on the "candidate gene approach". We hypothesize that a gene coding for a structural or a functional protein important in the physiology of photoreceptors may be defective or absent in patients in the physiology of photoreceptors may be defective or absent in patients with retinitis pigmentosa or other inherited retinal degenerations. The genes corresponding to some of these candidate proteins, such as interphotoreceptor retinoid-binding protein, various transducing subunits, subunits of cyclic-GMP phosphodiesterase, S- antigen, mitochondrial proteins, and rhodopsin, have been isolated by other investigators or by the project laboratory. We intend to use molecular genetics techniques to determine whether mutations of one or more of the candidate genes play a role in some hereditary retinal degeneration.